Refrigerator

ABSTRACT

A refrigerator which includes a discharge part having a drain pipe to receive defrost water from an evaporator and to discharge the defrost water, and a drain valve coupled with the drain pipe, to discharge the defrost water and selectively permit or intercept inflow of the external air. The drain valve includes a connection part to connect the discharge part, a valve body having a defrost water flowing hole communicating with the discharge part along a moving direction of the defrost water, and an air flowing port communicating with the defrost water flowing hole traversely to the moving direction of the defrost water, a backflow preventing part coupled with the valve body, to discharge the defrost water to the outside and intercept flowing of external air, and an open/close member having a passing hole communicating with the defrost water flowing hole along the moving direction of the defrost water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2005-0050150, filed on Jun. 11, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerator. More particularly, to a refrigerator with a simplified structure capable of preventing external air from flowing in a storage chamber when pressure of the storage chamber and external pressure are well balanced, and simultaneously discharging defrost water to the outside, and also easily opening a door by flowing external air in the storage chamber when pressure of the storage chamber changes as a result of opening and closing the door.

2. Description of the Related Art

Generally a conventional refrigerator includes a refrigerating compartment, a refrigerator body having a component compartment to receive therein several devices such as a compressor and a condenser, and a door to open and close an opening of the refrigerating compartment.

An evaporator to generate cool air, a defrost heater to remove frost deposited on the evaporator, and a drain receiving unit to receive defrost water from the evaporator, generated by defrosting it are provided in the refrigerator body. The defrost water received in the drain receiving unit is discharged to a water collecting tray provided in the component compartment through a discharge pipe.

In this conventional refrigerator, since external air whose temperature is higher than air inside the refrigerating compartment flows into an inside of the refrigerating compartment as the door is open and then closed, the air inside the refrigerating compartment is contracted because of a temperature difference between the internal air of the refrigerating compartment and the external air flowing into the refrigerating compartment, and the internal air of the refrigerating compartment is pushed to the evaporator side whereby a cooling fan to lower the enhanced temperature of the refrigerating compartment is driven. Thus, the door is not smoothly opened because of a change in pressure of the refrigerating compartment. In order to solve this problem, there has been proposed a device to remove negative pressure.

As an example of this negative pressure removing device, Korean Patent Application No. 1997-0067582 discloses a pressure removing device including an auxiliary absorbing pipe provided in one side of a discharge hose, through which external air is absorbed, and a valve body on which an open/close part is mounted, coupled with an end of the auxiliary absorbing pipe, to thereby open and close an air absorbing port.

When the door is opened, the air absorbing port is opened by the open/close part, through which external air flows into a refrigerating compartment, and thus, the door is smoothly opened since a difference external pressure and internal pressure of the refrigerating compartment is settled. In addition, after air flows into the refrigerator, the open/close part again closes the air absorbing port to thereby prevent external air from flowing into inside the refrigerator.

However, in this conventional negative pressure removing device, the valve body to flow external air and a discharge hose through which defrost water passes should be separately manufactured and assembled, thereby making it uneasy to manufacture them and troublesome to assemble.

Further, the valve body to flow external air has a complicated structure in that it includes an open/close part to confine flowing of air, a fixed part to fix the open/close part, a coupling hole corresponding to the fixed part, a recess part formed inside the open/close part, a valve cover, a fixed projection, an engaging boss corresponding to the fixed projection, and a fixed recess into which the fixed part is inserted, thereby causing the number of components to increase and making it uneasy to manufacture it.

Since the valve body having a complicated structure as described above is mounted projectedly on one side of the discharge hose, and thus, an external appearance thereof is not slim, and it occupies a large space for installation.

SUMMARY OF THE INVENTION

Accordingly, it is an aspect of the present invention to provide a refrigerator capable of preventing external air from flowing into inside a storage chamber when pressure of the storage chamber and external pressure are well balanced, and simultaneously discharging defrost water to the outside, and easily opening a door by flowing external air into an inside the storage chamber when pressure of the storage chamber changes as a result of opening and closing the door.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

These and/or other aspects of the present invention are achieved by providing a refrigerator including a refrigerator body having at least one storage compartment and an evaporator to generate cool air to be supplied into the storage compartment, the refrigerator including a discharge part comprising a drain pipe to receive defrost water from the evaporator and to discharge the defrost water, and a drain valve coupled with a terminal of the drain pipe, to discharge the defrost water and selectively permit or intercept inflow of the external air.

It is another aspect of the present invention to provide a refrigerator including a refrigerator body having at least one storage compartment and an evaporator to generate cool air to be supplied into the storage compartment, the refrigerator including a discharge part including a drain pipe to receive defrost water from the evaporator and to discharge the defrost water, and a drain valve coupled with a terminal of the drain pipe, to discharge the defrost water and to selectively permit or intercept inflow of the external air. The drain valve includes a connection part to connect the discharge part, a valve body having a defrost water flowing hole communicating with the discharge part along a moving direction of the defrost water, and an air flowing port communicating with the defrost water flowing hole traversely to the moving direction of the defrost water, which is coupled with the connection part, a backflow preventing part coupled with the valve body to thereby communicate, to discharge the defrost water to the outside and intercept flowing of external air, and an open/close member having a passing hole communicating with the defrost water flowing hole along the moving direction of the defrost water, provided inside the valve body so as to be elevatable between the connection part and the backflow preventing part.

The open/close member includes a main body having the passing hole formed therein, and a flange part formed on at least one terminal region of the main body.

The vale body includes a support part, the support part being engaged with the flange part at a closed state wherein the open/close member closes the air flowing port, to thereby support the open/close member.

The backflow preventing part includes a cut part, wherein the cut part being opened by the weight of the defrost water flown into the backflow preventing part.

The backflow preventing part is shaped with a funnel in section.

The air flowing port penetrates along a circumferential direction of the valve body so as to communicate with the defrost water flowing hole.

The discharge part includes a drain receiving part to receive the defrost water from the evaporator, and including a drain port, and a drain pipe, one side of which is connected with the discharge part and the other side of which is connected withthe drain valve, to thereby guide the defrost water from the drain receiving part to the drain valve.

It is yet another aspect of the present invention to provide a refrigerator including at least one storage compartment, a refrigerator body having a component compartment to receive therein a variety of components, at least one door to open and close the storage compartment, and an evaporator provided in the rear of the storage compartment, to generate cool air to be supplied into the storage compartments, the refrigerator including a drain receiving part to collect defrost water from the evaporator generated when the evaporator is defrosted, a drain pipe to discharge the defrost water collected in the drain receiving part to the component compartment, and a drain valve coupled with a terminal of the drain pipe in a lengthwise direction of the drain pipe, to selectively permit or intercept flowing of internal air of the component compartment perpendicular to a discharge direction of the defrost water.

The drain valve includes a connection part connected with the drain pipe, a valve body coupled with the connection part, and including a defrost water flowing hole communicating with the drain pipe along a moving direction of the defrost water and an air flowing port communicating with the defrost water flowing hole perpendicular to the discharge direction of the defrost water, a backflow preventing part coupled with the valve body to communicate, and to discharge the defrost water to an outside and to intercept external air from flowing thereinto, and an open/close member provided inside the valve body so as to be elevatable between the connection part and the backflow preventing part, and including a passing hole communicating with the defrost water flowing hole along the discharge direction of the defrost water.

The open/close member includes a main body including the passing hole therein, and a flange part formed on at least one terminal region of the main body.

The valve body including a support part, the support part being engaged with the flange part when the open/close member closes the air flowing port, to thereby support the open/close member.

The backflow preventing part including a cut part, the cut part being opened by a weight of the defrost water flown into the backflow preventing part.

It is yet another aspect of the present invention to provide a refrigerator including at least one storage compartment, a refrigerator body having a component compartment to receive therein a variety of components, at least one door to open and close the storage compartment, and an evaporator provided in the rear of the storage compartment, to generate cool air to be supplied into the storage compartments, the refrigerator including a drain pipe to discharge the defrost water collected in the drain receiving part to the component compartment, and a drain valve provided in a terminal of the drain pipe, including an air flowing port to flow air transversely to a discharge direction of the defrost water, an open/close member elevatably provided to thereby open and close the air flowing port, and to pass the defrost water when the air flowing port is closed, and a backflow preventing part disposed in a lower side of the open/close member, to discharge the defrost water due to a weight thereof, and to intercept inflow of external air.

The open/close member includes a main body having a passing hole through which the defrost water passes, and a flange part formed on at least one terminal region of the main body.

The drain valve further includes a valve body elevatably accommodating the open/close member, and including the air flowing port along a circumferential direction thereof, and a defrost water flowing hole communicating with the passing hole internally along the discharge direction of the defrost water so that the defrost water can pass.

The backflow preventing part including a cut part, the cut part being opened by a weight of the defrost water flown into the backflow preventing part.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 illustrates a door-open state of a refrigerator according to an embodiment of the present invention;

FIG. 2 schematically illustrates an installation region of a drain valve according to an embodiment of the present invention;

FIG. 3 illustrates a connection part and an open/close member of the drain valve of FIG. 2 disassembled from a valve body;

FIG. 4 illustrates a state that the open/close member of the drain valve of FIG. 2 closes an air flow port;

FIG. 5 is a sectional view of FIG. 4;

FIG. 6 illustrates a state that the elevated open/close member of the drain valve of FIG. 2 opens an air flow port; and

FIG. 7 is a sectional view of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

As shown in FIGS. 1 and 2, a refrigerator according to the present invention comprises storage compartments 3 a and 3 b to provide a refrigerating compartment 3 a and a freezing compartment 3 b by partitioning them vertically with a partition 2, a refrigerator body 1 having a component compartment to receive therein a variety of components, and doors 7 a and 7 b to open and close the refrigerating compartment 3 a and the freezing compartment 3 b, respectively.

In a rear of each of the refrigerating and freezing compartments 3 a and 3 b is provided an evaporator 9 to generate cool air. Cool air generated by the evaporator 9 flows into the refrigerating and freezing compartments 3 a and 3 b through a cool air discharge port 4 a formed by penetrating a rear plane of each of the refrigerating and freezing compartments 3 a and 3 b, and frost deposited on the evaporator 9 is removed by a defrost heater (not shown). In FIGS. 1 and 2, an evaporator 9 and a cool air discharge port 4 a are shown, but each evaporator 9 is positioned in the respective rear sides of the refrigerating compartment 3 a and the freezing compartment 3 b, and each cool air discharge port is formed on the refrigerating compartment 3 a and the freezing compartment 3 b respectively.

As shown in FIG. 2, discharge parts 21, 22 and 23 are provided below the evaporator 9, the discharge parts 21, 22 and 23 receiving defrost water generated from the evaporator 9 when a defrost heater (not shown) operates, and discharging it toward a water collecting tray 6 provided in the component compartment 5.

The discharge parts 21, 22 and 23 receive the defrost water from the evaporator 9, and each comprises a drain receiving part 22 formed with the discharge port 21, and a drain pipe 23 connected with the discharge port 21, to discharge the defrost water received in the drain receiving part 22 toward the water collecting tray 6.

A terminal of the drain pipe 23 is combined with a drain valve 30 to discharge the defrost water moving downward along the drain pipe 23, and flow air into and to intercept flowing of the air into the storage compartments.

As shown in FIG. 3, the drain valve 30 comprises a connection part 31 connected with the drain pipe 23, a valve body 35 coupled with the connection part 31, and comprising an air flowing port 33, a backflow preventing part 37 coupled with the valve body 35 to communicate with each other, to discharge the defrost water to the outside and intercept flowing of external air, and an open/close member 40 elevatably provided within the valve body 35, to open and close the air flowing port 33.

The connection part 31 comprises a central region vertically penetrating it, to thereby have a hollow pipe-shaped inner part. Accordingly, a part of the drain pipe 23 may be accommodated in the connection part 31 so as to communicate with an inner space of the valve body 35.

The valve body 35 is internally formed with a defrost water flowing hole 32 (shown in FIG. 5) penetrating in a vertical direction along which the defrost water moves, to thereby communicate with the drain pipe 23. Along a circumferential direction of the valve body 35 is formed an air flowing port 33 penetrating laterally, to thereby communicate with the defrost water flowing hole 32. Thus, the defrost water having passed through the drain pipe 23 flows into the defrost water flowing hole 32, and external air laterally flow into the air flowing port 33.

The open/close member 40 is elevatably installed within the valve body 35 so that it is movable between a close position to close the air flowing port 33 (see FIG. 5) and an open position to open the air flowing port 33 (see FIG. 7), between the connection part 31 and the backflow preventing part 37.

Before the external air whose temperature is relatively higher than the internal temperature of the storage compartments 3 a and 3 b after the doors 7 a and 7 b are opened and closed, flows into the storage compartments 3 a and 3 b, whereby the pressures of the storage compartments 3 a and 3 b change, the open/close member 40 remains at a closed state to close the air flowing port 33 (see FIGS. 5 and 6) so as to block external air from being flown into the inside of the drain valve 30.

When opening and then closing the doors 7 a and 7 b, air of the storage compartments 3 a and 3 b is contracted because the external air flows into the inside of the storage chambers 3 a and 3 b. This causes a change in pressures of the storage compartments 3 a and 3 b and the open/close member 40 closing the air flowing port 33 moves upwardly as illustrated in FIGS. 6 and 7. According to this, external air flows into the open air flowing port 33, and the flown external air passes through a passing hole 42 to be described later and the defrost water flowing hole 32 and is flown into the storage compartments by way of the drain hoses.

This open/close member 30 comprises a main body 41 formed with a passing hole 42 penetrating in the vertical direction along which the defrost water moves, and flange parts 43 formed on both end regions of the main body 41.

The defrost water flowing into the defrost water flowing hole 32 of the valve body 35 passes through the passing hole 42, and the external air flowing into the air flowing port 33 passes through the air flowing port 33 which is open.

The pair of flanges 43 is engaged with a support part 34 formed inside the valve body 35, at the close position (see FIG. 5) of the open/close member 40, to thereby support the close position of the open/close member 40 (see FIG. 5).

The backflow preventing part 37 is shaped with a funnel having a diameter which gradually narrows from up to down, coupled with a lower side of the valve body 35. Hence, the backflow preventing part 37 is formed of rubber, for example. However, the material of the backflow preventing part is not limited hereto, and may vary as necessary.

The backflow preventing part 37 communicates with the valve body 35 and the open/close member 40 through a upper opening thereof, and thus, the defrost water having passed through the defrost water flowing hole 32 of the valve body 35 and the passing hole 42 of the open/close member 40 is flown.

The lower end region of the backflow preventing part 37 comprises a cut part 36 to discharge the defrost water. According to this, the defrost water flown into the backflow preventing part 37 moves downward and is discharged to the water collecting tray 6 through the cut part 36.

The cut part 36 is opened by a weight of the defrost water collected in the lower end region of the backflow preventing part 37, and is then closed when the defrost water is discharged from the backflow preventing part 37 through the open cut part 36, whereby external air does not flow into the inside of the backflow preventing part 37 through the cut part 36.

Hereinafter, operations of the open/close member 40 of the drain valve 30 due to a change in pressure of the storage compartment generated after the doors are opened and closed will be described with reference to FIGS. 4 to 7.

As illustrated in FIGS. 4 and 5, the open/close member 40 closes the air flowing port 33 of the valve body 35. Here, as the flange part 43 of the open/close member 40 is engaged with the support part 34 of the valve body 35, the open/close member 40 maintains the close position to close the air flowing port 33 of the valve body 35, and the passing hole 42 of the open/close member 40 communicates with the drain pipe 23, the defrost water flowing hole 32 and the backflow preventing part 37.

According to this, the defrost water generated as a result of defrosting the evaporator 9 first drops to the drain receiving part 22 and moves downward along the drain pipe 23 through the discharge port 21. The defrost water moving along the drain pipe 23 is discharged to the water collecting tray 6 through the drain valve 30. Here, the defrost water flown into the drain valve 30 from the drain pipe 23 passes through the defrost water flowing hole 32 of the valve body 35 and the passing hole 42 of the open/close member 40 and drops to the lower region of the backflow preventing part 37. At this time, since the cut part 36 of the backflow preventing part 37 is opened by the weight of the defrost water, the defrost water is discharged to the water collecting tray 6 through the open cut part 36. The cut part 36 which was opened by the weight of the defrost water is again closed after the defrost water has been discharged, and thus, air does not flow into the inside of the drain valve 30 through the cut part 36.

When a user opens the doors 7 a and 7 b and closes them again, external air flows into the refrigerating and freezing compartments 3 a and 3 b. At this time, the air in the refrigerating and freezing compartments 3 a and 3 b is contracted, thereby causing a change in pressure of the storage compartments 3 a and 3 b. Due to this change, the open/close member 40 of the drain valve 30 moves upward as illustrated in FIGS. 6 and 7. The air flowing port 33 of the valve body 35 is opened by upward movement of the open/close member 40 that has closed the air flowing port 33, and external air flows inside the valve body 35 through the air flowing port 33. The air which flows inside the valve body 35 flows into the drain pipe 23 through the passing hole 42 and the defrost water flowing hole 32 of the open/close member 40. The air flown into the drain pipe 23 continuously moves upward and flows inside the refrigerating and freezing compartments 3 a and 3 b, thereby settling the change in pressure of the storage compartments 3 a and 3 b. Thus, the doors 7 a and 7 b can be easily opened with a little force. After the change in pressure of the storage compartments 3 a and 3 b is settled as air flows into the refrigerating and freezing compartments 3 a and 3 b, the open/close chamber 40 of the drain valve 30 moves downward by its self weight and is then restored to the closed position as illustrated in FIGS. 4 and 5.

The open/close member 40 having the passing hole 42 to flow air into and to intercept flowing of the air into the refrigerating and freezing compartments 3 a and 3 b and to pass the defrost water is elevatably provided inside the valve body 35 of the drain valve 30. According to this, the drain valve 30 performing two functions of discharging the defrost water and flowing air into the refrigerating and freezing compartments 3 a and 3 b with a simplified structure is provided.

Further, since the drain valve 30 externally appears slim, it can be easily installed even at a narrow space. Also, since inner diameters of the passing hole 42 and the drain pipe 23 are substantially similar, external air can be promptly flown into the drain pipe 23.

As described above, according to the present invention, the flowing of external air into the storage compartments can be prevented and at the same time the defrost water can be discharged to the outside through the drain valve with a simplified structure when the internal pressure of the storage chambers and external pressure are well balanced. Even when a change occurs in the pressure of the storage compartments generated as the doors are opened and closed, external air can be flown inside the storage compartments so as to facilitate opening of the doors.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A refrigerator comprising a refrigerator body having at least one storage compartment and an evaporator to generate cool air to be supplied into the storage compartments, the refrigerator comprising: a discharge part comprising a drain pipe to receive defrost water from the evaporator and to discharge the defrost water; and a drain valve coupled with a terminal of the drain pipe, to discharge the defrost water and to selectively permit or to intercept inflow of external air.
 2. A refrigerator comprising a refrigerator body having at least one storage compartment and an evaporator to generate cool air to be supplied into the storage compartments, the refrigerator comprising: a discharge part having a drain pipe to receive defrost water from the evaporator and to discharge the defrost water; and a drain valve coupled with a terminal of the drain pipe, to discharge the defrost water and to selectively permit or to intercept inflow of external air, wherein the drain valve comprises: a connection part to connect the discharge part to the drain valve, a valve body having a defrost water flowing hole communicating with the discharge part along a moving direction of the defrost water, and an air flowing port communicating with the defrost water flowing hole traversely to a moving direction of the defrost water, which is coupled with the connection part, a backflow preventing part coupled with the valve body to thereby communicate, to discharge the defrost water to an outside and to intercept flowing of the external air, and an open/close member comprising a passing hole communicating with the defrost water flowing hole along the moving direction of the defrost water, provided inside the valve body so as to be elevatable between the connection part and the backflow preventing part.
 3. The refrigerator according to claim 2, wherein the open/close member comprises: a main body including the passing hole; and a flange part formed on at least one terminal region of the main body.
 4. The refrigerator according to claim 3, wherein the valve body further comprises a support part, the support part being engaged with the flange part at a closed state wherein the open/close member closes the air flowing port, to thereby support the open/close member.
 5. The refrigerator according to any claim 2, wherein the backflow preventing part comprises a cut part, the cut part being opened by a weight of the defrost water which flows into the backflow preventing part.
 6. The refrigerator according to claim 5, wherein the backflow preventing part is shaped with a funnel in section.
 7. The refrigerator according to claim 6, wherein the air flowing port penetrates along a circumferential direction of the valve body so as to communicate with the defrost water flowing hole.
 8. The refrigerator according to claim 2, wherein the discharge part comprises: a drain receiving part to receive the defrost water from the evaporator, and comprising a drain port; and a drain pipe, one side of which is connected with the discharge part and the other side of which is connected to the drain valve, to thereby guide the defrost water from the drain receiving part to the drain valve.
 9. A refrigerator comprising at least one storage compartment, a refrigerator body having a component compartment to receive therein a variety of components, at least one doors to open and close the storage compartment, and an evaporator provided in a rear of the storage compartment, to generate cool air to be supplied into the storage compartment, comprising: a drain receiving part to collect defrost water from the evaporator generated when the evaporator is defrosted; a drain pipe to discharge the defrost water collected in the drain receiving part to the component compartment; and a drain valve coupled with a terminal of the drain pipe in a lengthwise direction of the drain pipe, to selectively permit or to intercept flowing of internal air of the component compartment perpendicular to a discharge direction of the defrost water.
 10. The refrigerator according to claim 9, wherein the drain valve comprises: a connection part to connect the drain valve with the drain pipe; a valve body coupled with the connection part, and comprising a defrost water flowing hole communicating with the drain pipe along a moving direction of the defrost water and an air flowing port communicating with the defrost water flowing hole perpendicular to the discharge direction of the defrost water; a backflow preventing part coupled with the valve body to communicate, to discharge the defrost water to an outside and to intercept external air from flowing thereinto; and an open/close member provided inside the valve body so as to be elevatable between the connection part and the backflow preventing part, and comprising a passing hole communicating with the defrost water flowing hole along the discharge direction of the defrost water.
 11. The refrigerator according to claim 10, wherein the open/close member comprises: a main body including the passing hole; and a flange part formed on at least one terminal region of the main body.
 12. The refrigerator according to claim 11, Wherein the valve body further comprises a support part, the support part being engaged with the flange part when the open/close member closes the air flowing port, to thereby support the open/close member.
 13. The refrigerator according to claim 10, wherein the backflow preventing part comprises a cut part, the cut part being opened by a weight of the defrost water which flows into the backflow preventing part.
 14. A refrigerator comprising at least one storage compartment, a refrigerator body having a component compartment to receive therein a variety of components, at least one door to open and close the storage compartment, and an evaporator provided in a rear of the storage compartment, to generate cool air to be supplied into the storage compartment, comprising: a drain pipe to discharge the defrost water collected in the drain receiving part to the component compartment; and a drain valve provided in a terminal of the drain pipe, and comprising: an air flowing port to flow air transversely to a discharge direction of the defrost water, an open/close member elevatably provided, to thereby open and close the air flowing port, and to pass the defrost water when the air flowing port is closed, and a backflow preventing part disposed in the lower side of the open/close member, to discharge the defrost water due to the self weight thereof, and intercept inflow of external air.
 15. The refrigerator according to claim 14, wherein the open/close member comprises: a main body comprising a passing hole through which the defrost water passes; and a flange part formed on at least one terminal region of the main body.
 16. The refrigerator according to claim 15, wherein the drain valve further comprises: a valve body elevatably accommodating the open/close member, and including the air flowing port along a circumferential direction thereof, and a defrost water flowing hole communicating with the passing hole internally along the discharge direction of the defrost water so that the defrost water can pass therethrough.
 17. The refrigerator according to claim 14, wherein the backflow preventing part comprises a cut part, the cut part being opened by a weight of the defrost water which flows into the backflow preventing part. 